After last year’s WWDC, I argued in Fertile Ground that iOS 7 was a huge opportunity for developers: with so much change required for established apps to remain competitive, anyone making a new app had a big advantage and a great chance of establishing a foothold. Established markets were plowed over and shaken up, leaving opportunity.

This year, the opportunity is different, but even bigger. With iOS 8’s new Extensions, entire categories of apps that were previously impossible are now possible. Rather than shaking up the existing apps, Apple has created vast new markets that are currently empty.

We’ll see the easy stuff on day one, of course. Apps like Instapaper can stop using clunky Javascript bookmarklets and URL schemes to shuttle data out of Safari or between apps. Photo apps can now operate on the photo library as first-class citizens, just like the built-in Photos app. Notification Center can now contain status message widgets, shortcuts for launchers, quick-entry fields for task managers or note-taking apps, and almost anything else an app wants to put there (with user permission, of course). Almost every existing app can now do something very useful that it couldn’t do before.

But existing apps were all written by people like me who have been solidifying the assumption in our minds over our entire iOS careers that these features simply aren’t and never will be possible on iOS. We never thought we’d get these. It’s going to take a while before we internalize these new abilities and forget the old restrictions.

The first amazing, forehead-smacking innovations with iOS 8 won’t come from us: they’ll come from people who are coming to iOS development from this point forward, never having known a world with the old restrictions.